Not unlike a grim round of the game “Would You Rather?” — in which the choices are getting eaten by a shark or running out of oxygen underwater — “47 Meters Down” stars Mandy Moore and Claire Holt (“The Originals”) as sisters facing not one but two potential ways to die.

And while it’s no “Jaws,” or even “The Shallows,” “47 Meters Down” is a lean and mean little B-movie that skillfully plays on our fear of what lies beneath the waves. Coming into this thriller with a fairly unimpressive horror résumé, director Johannes Roberts (“The Other Side of the Door”) ratchets up the tension with precision, making sure that we’re always aware of the presence of the sharks and the impending absence of air in the scuba tanks.

Kate (Holt) joins her sister Lisa (Moore) on a Mexican vacation, but Lisa eventually breaks down and admits that the reason her boyfriend didn’t come instead was because he dumped her for being too dull. It’s understandable, then, that after a night out where the ladies meet two cute locals, that Lisa can talk the normally risk-averse Kate into scuba-diving in a cage to interact with the local shark population.

Captain Taylor (Matthew Modine) is an amiable enough seaman, but Lisa is right to balk at the rickety-looking winch and cage in question. The device works when it sends the guys down, but for the girls, the chain snaps, sending Kate and Lisa plummeting down the titular 47 meters to the ocean floor. They can’t just swim up, first because of the sharks circling overhead, and later because they’ll get the bends if they don’t spend five minutes at a median level before surfacing. (And that five minutes would have to be spent amidst the aforementioned sharks.)

The characterization in the script by Roberts and Ernest Riera is fairly minimal, but it’s enough to create the situation and the perils therein. (Kate is a trained scuba diver, while Lisa is on her very first plunge.) There’s no B-story here, either; once the women are stuck in their situation, it’s almost entirely on them to figure out how to survive. (Captain Taylor is on the radio, but they can only get his signal when one of them swims closer to the surface.) But even for a tale that’s this linear, the writers manage to work in a surprise or two.

The Dominican Republic stands in for Mexico, with water tanks in Britain subbing for the Atlantic, but “47 Meters Down” never feels stagebound; when Lisa swims out to get a flashlight, and then finds herself lost in the dark, unsure how to get back to the cage, the ocean feels terrifyingly immense and infinite.

Moore and Holt both give fine performances, particularly with the impediment of wearing oxygen masks for most of the movie, and they convey their degrees of panic and desperation effectively, even in a cloud of air bubbles.

This is a B-movie in the best sense, and it harkens back to an era when major studio releases weren’t just B-movies with stars and a budget. It’s lean and mean, focused and direct, and the jolts are both effective and well earned. Roberts and editor Martin Brinkler keep their ticking clock tightly wound, deviously making our heroines’ plight seemingly more hopeless with each passing moment.

'A Walk to Remember' Turns 15: The 15 Moments That Made Us Cry (Photos)

It's been 15 years since Mandy Moore and Shane West played two lovestruck North Carolina teens in the Nicholas Sparks adaptation "A Walk to Remember." Jamie and Landon's unlikely romance caused all sorts of feels among moviegoers when it came out in 2002. Click through to take a trip down memory lane and see the 15 moments that made us cry. Beware of 15-year-old spoilers!

When Jamie agrees to help Landon with his lines for a play, she says, “You have to promise you won’t fall in love with me.”

"That's not a problem," he responds, laughing. Obviously, this wouldn't be a tear-jerker on its own, but given that he eventually does fall in love with her and we understand why that was a condition of hers... yep. Tear-jerker.

Warner Bros.

When Jamie sings and Landon improvises

When Jamie sings "Only Hope" during their performance, Landon improvises the ending and kisses her in front of the entire audience. It's a super intimate moment that marks the beginning of their powerful relationship.

Warner Bros.

When Landon and Jamie were in two places at once

On their first date, Landon helps Jamie cross one thing off of her bucket list: being in two places at once. He takes her to the state line where she can have one foot in Virginia and the other in their home state of North Carolina. Landon goes to extreme lengths to prove his devotion and love to her, and obviously, we later realize why Jamie has a bucket list at all.

Warner Bros.

Jamie gets a tattoo

Another thing on her bucket list was to get a tattoo. When Landon puts a temporary tattoo of a butterfly on her shoulder, the thoughtful gesture made girls around the world get weepy.

Warner Bros.

Their kiss

Landon tells Jamie, "I might kiss you," to which she responds, “I might be bad at it.” He says, “That’s not possible.”

Warner bros.

When Landon names a star after her

Arguably the most romantic moment of all time, Landon names a star after Jamie, which prompts her to finally tell him she loves him.

Warner Bros.

When Jamie finally tells him she's sick

It's one of the most heartbreaking scenes in the movie -- when Jamie tells Landon she has leukemia.

“No, you’re 18, you’re perfect,” Landon says. She responds, “No, I found out two years ago, and I’ve stopped responding to treatments.”

When Landon asks his dad for help

Landon wants to help Jamie in any way he can, so he drives out to his estranged father's house to ask the cardiologist for help. His dad eventually agrees to pay for Jamie's home care.

Warner Bros.

Landon never leaves Jamie's side

After Jamie faints, she is admitted to the hospital, where Landon never leaves her side.

Warner Bros.

Landon tells his mom Jamie's changed him

"She makes me want to be different. Better," he tells his mom.

Warner Bros.

When he learns to dance for Jamie

Landon asks his mom to teach him how to dance in an adorable and tear-inducing mother-son moment.

Warner Bros.

When he proposes

Enough said.

Warner Bros.

When Landon tells Jamie she'll never be without him

"I'm scared of not being with you," she says, to which Landon responds, "Oh, baby, that will never happen."

Warner Bros.

Their wedding

Jamie, extremely weak at this point, walks down the aisle with her dad who formerly disapproved of her relationship with Landon.

Warner Bros.

When Landon returns four years later

When Landon returns to see Jamie's dad four years after her death, he tells him, "I'm sorry she never got her miracle." Her dad responds, "She did. It was you."

A sob fest ensues, especially when the movie ends with the following sentence: “Love is like the wind. You can’t see it, but you can feel it.”

It's been 15 years since Mandy Moore and Shane West played two lovestruck North Carolina teens in the Nicholas Sparks adaptation "A Walk to Remember." Jamie and Landon's unlikely romance caused all sorts of feels among moviegoers when it came out in 2002. Click through to take a trip down memory lane and see the 15 moments that made us cry. Beware of 15-year-old spoilers!

Alonso Duralde, TheWrap's lead movie critic, has written about film for Movieline, Salon, MSNBC.com. He also co-hosts the Linoleum Knife podcast and regularly appears on What the Flick?! (The Young Turks Network). Senior Programmer for the Outfest Film Festival in Los Angeles and a pre-screener for the Sundance Film Festival, he is also a consultant for the USA Film Festival/Dallas, where he spent five years as artistic director. A former arts and entertainment editor at the Advocate, he was a regular contributor to "The Rotten Tomatoes Show" on Current. He is the author of two books: "Have Yourself a Movie Little Christmas" (Limelight Editions) and "101 Must-See Movies for Gay Men" (Advocate Books).